Intersections

Intersections occur when two or more roadways cross paths. Individual drivers along the roadways have individual destinations that lead to conflict points within the intersections. Because of these conflicts, it is no surprise that the majority of accidents occur within intersections. Therefore, it is a priority for traffic engineers to minimize the risk to drivers by increasing safety within intersections. As a trade off, traffic engineers have to try to maximize the efficiency and mobility within the intersection. The delicate balance between moving traffic safely and efficiently has led to various types of intersection treatments.

The type of traffic control used within an intersection is determined by a variety of factors. There are strict guidelines outlined in the Federal Highway Administration’s Manual on Uniform Traffic Control Devices (MUTCD). The type of intersection traffic control is determined by a variety of factors including: traffic volumes, sight distance, crash histories, speed limits, and street classifications.

This page will highlight the various intersection types starting with the most basic intersection type and progressing to the most complex.

Uncontrolled IntersectionUncontrolled intersections are the most minimal form of intersection traffic control. These intersections are low traffic volumes, low speed roadways typically in residential neighborhoods that rely on the Uniform Vehicle Code (UVC) to determine right-of-way. The code states that “the driver of the vehicle on the left shall yield the right-of-way to all vehicles approaching from the right that are close enough to constitute an immediate hazard”. More simply stated; a driver must yield to the vehicles on their right. Occasionally, uncontrolled intersections need additional traffic control, but do not warrant the higher levels of traffic control shown below. In these special cases, various forms of “traffic calming” can be used to aid in the neighborhood traffic. Traffic calming is discussed in more detail in the following

When the traffic increases to a point where the UVC can no longer safely pass traffic, right-of-way for approaching vehicles is assigned with the use of signs. Prior to installation, an engineering study is performed to determine the need and type of signage. STOP or YIELD signs are the commonly used signs to assign this priority. See the following link for more information: http://www.ci.billings.mt.us/2087.

Traffic Signals/Roundabouts

Traffic signals and/or roundabouts are used for the more complex intersections along heavily traveled roadways. Both traffic signals and roundabouts have advantages/disadvantages over the other. However, both intersection treatments are used to progress higher level traffic through intersections in the safest, most efficient way possible. Traffic engineers have to take into account a variety of factors when determining whether to use a traffic signal or a roundabout. Information for both traffic signals and roundabout can be found on the following links:

Citizen RequestsThe City is constantly monitoring problematic intersections for potential solutions. Each intersection presents unique characteristics that can be better handled with one intersection treatment over the others. A roundabout may work at one intersection, whereas a traffic signal or 4-way stop signs are a better fit at another intersection. The City takes our role in solving traffic problems very seriously, yet the ultimate burden of safety rests with you, the motorist. Please use the contact information below to discuss a particular intersection that you think could be improved: